A process for depositing coatings, and particularly erosion-resistant coatings suitable for protecting surfaces of a gas turbine engine blisk having a disk and integral blades with flowpath surfaces that are susceptible to erosion. The processing involves placing the blisk adjacent a coating material source in an apparatus configured to evaporate the source and generate coating material vapors. The blisk is oriented relative to the coating material source so that the axis of rotation of the blisk is within about forty-five degrees of a linear path that the coating material vapors flow from the coating material source to the blisk, and more erosion-susceptible flowpath surfaces of the blades face the coating material source. The blisk is then rotated about its axis of rotation while the coating material source is evaporated to preferentially deposit the coating material vapors and form a coating on the erosion-susceptible flowpath surfaces of the blades and disk.